1. Field of the Invention
The present invention relates to a vehicle lighting device employed for a headlamp or a rear combination lamp of a vehicle.
2. Description of the Related Art
In recent years, a self-light emitting semiconductor-type light source such as a light emitting diode has been employed as a light source for vehicle lighting device, such as a headlamp.
Such a semiconductor-type light source configures a light source unit together with a reflector for reflecting light therefrom forward of a lighting device and is arranged in a lamp room which is made up of a housing and an outer lens.
The semiconductor-type light source that is employed as a light source for vehicle lighting device has been developed to achieve high intensity of illumination in order to enhance an effect of illumination. With a need for such achievement of high intensity of illumination, a heat rate increases as well. As a measure for mitigating a temperature rise of this semiconductor-type light source, it has been a routine practice to intensively arrange the semiconductor-type light source and the reflector while this heat sink member is used as a base.
On the other hand, in general, a reflector is die-molded with a thermoplastic synthetic resin material with its good moldability for the sake of forming a reflection surface having its complicated curved face.
In a lighting device employing such a synthetic resin-based reflector, for example, as disclosed in Japanese Patent Application Laid-open No. 2008-41557, it is known that the lighting device is provided with: a first reflector which is arranged to cover the periphery of a semiconductor-type light source fixed to a heat sink member, for reflecting light emitted from the semiconductor-type light source so as to be oriented in a predetermined direction; and a second reflector for causing the reflected light from the first reflector to be incident thereto and then reflecting the incident light so as to be oriented forward of the lighting device.
The first reflector and the second reflector are integrally molded with each other and a shade is also integrally formed at a communication portion between these reflectors. In this manner, a part of the reflected light from the first reflector is shaded with the shade so that a predetermined light distribution pattern can be obtained.
While a light distribution pattern is determined depending on an edge shape of a shade, the shade is integrally formed with the first reflector and the second reflector as described previously. Therefore, plural types of reflectors having their different edge shapes of the shade must be provided in order to cope with specifications of a variety of countries, which is disadvantageous in terms of cost efficiency.
In addition, in a case where a vehicle is stopped on slope daytime, if sunlight is caused to be incident to the second reflector from the front side of the vehicle, the sunlight that is reflected by the second reflector goes along a path in an opposite direction to that of an optical path forming a light distribution and optically focuses on the shade. Thus, the shade is deformed by being subjected to a thermal effect of such solar light and such deformation can adversely affect light distribution performance.
Therefore, the present invention provides a vehicle lighting device which is capable of causing a shade to maintain compatibility to cope with specifications of a variety of countries and is capable of avoiding lowering of the light distribution performance due to the thermal effect of the shade even if incidence of sunlight going back from a light distribution path takes place.